In a conventional assembly, the housing and the flap unit are each one-piece injection-molded parts and the flap unit is mounted in the housing, the flap unit having at least two flap elements and a connection section arranged between each two flap elements.
Such assemblies serve as control elements for gaseous or liquid media which are referred to below as fluids. The flap unit is mounted so as to pivot in the housing in such a way that a maximum throughput of the fluid is possible in an open position of the flap unit relative to the housing, and a minimal throughput or a blockage of the fluid is possible in a closed position. Such assemblies can be used, for example, in heating, ventilation and climate control systems, especially those installed in vehicles, in order to control the flow of fresh air or warm air.
It would be desirable to configure the two components of the assembly as one-piece injection-molded parts of which one is non-detachably integrated into the other. In fact, it is fundamentally possible to allow an injection-molded part to harden in a second one in such a way that the two injection-molded parts can move relative to each other. Such a method is known, for example, from DE 33 40 122 A1. In this method, a first injection-molded part is manufactured in a first mold. Then the first injection-molded part is removed from the first mold and placed into a second mold. Here, the first injection-molded part hardens to such an extent and acquires so much strength that an injection-molding material can be injected into the second mold, thus, for example, filling an opening of the first injection-molded part and hardening in it to form a second injection-molded part. The second injection-molded part can then move in the first injection-molded part, but it can be non-detachably connected to it. In any case, the essential advantage is achieved that the second injection-molded part does not have to be mounted onto the first one.
Since the first injection-molded part is already partially solidified before the second injection-molded part is made, the first injection-molded part already has undergone part of its unavoidable shrinkage before the material for the second injection-molded part is injected. The result of this can be that the second injection-molded part jams against the first injection-molded part when the second injection-molded part in turn shrinks. In particular with an assembly of the type mentioned above, the shrinkage of the connection section between two adjacent flaps causes the flaps to jam in the housing.
The objective of the invention is to improve an assembly of the type described above in such a way that the flap unit can be formed in the housing without impairing the mobility of the flap unit relative to the housing.